Elastomers, analysis

Table 1.5 Comparison of hyphenated thermogravimetric techniques for elastomer analysis ...

Other reported TG-MS applications concern polybutadiene [153], styrene-butadiene rubbers [153], gums [14], polyisoprenes [52], polyurethanes [144, 146, 147, 166], ABS [144], chlorosulphonated polyethylene elastomer [169, 170] and elastomer blends (NBR/SBR/ BR) [13]. Table 1.5 summarises the use of advanced TG-MS systems in elastomer analysis. 

POLYMERS FOR FIBERS AND ELASTOMERS ANALYSIS OF FILE 51 ON 01-MAR-83AT 15 50 16... 

Infrared (IR) spectra were recorded with a Bruker IFS 113 V FTIR spectrometer. The spectra of the model oligomers were obtained using KBr-pellets or bulk samples (melt). Thin films cast from DMA solution were used for elastomer analysis. 

Pliskin I and Tbkita N (1972) Bound rubber in elastomers analysis of elastomer-filler interaction and its effect on viscosity and modulus of composite systems, J Appl Polym Sci 16 473-492. 

Additional information on elastomer and SAN microstmcture is provided by C-nmr analysis (100). Rubber particle composition may be inferred from glass-transition data provided by thermal or mechanochemical analysis. Rubber particle morphology as obtained by transmission or scanning electron microscopy (101) is indicative of the ABS manufacturing process (77). (See Figs. 1 and 2.)... 

Shock isolation is also possible usiag the dampiag characteristics of FZ elastomer. Dynamic mechanical analysis iadicates multiple transitions and a broad dampiag peak. This dampiag can be enhanced usiag formulatioas containing both siUca and carbon black fillers. 

I.H. Gregory and A.H. Muhr, Stiffness and fracture analysis of bonded rubber blocks in simple shear, in Finite Element Analysis of Elastomers, ed. by D. Boast and V.A. Coveny, Professional Engineering Publications, Bury St. Edmunds, United Kingdom, 1999, pp. 265-274. 

Witsiepe, W.K., Segmented polyester thermoplastic elastomers, Adv. Chem. Ser., 129, 39, 1973. Srichatrapimuk V.W. and Cooper S.L., Infrared thermal analysis of pol3furethane block polymers, J. Macromol. Set Phys. B, 15, 267, 1978. 

Borgaonkar H. and Ramani K., Stability analysis in single screw extrusion of thermoplastic elastomers using simple design of experiments, Adv. Polym. Technol., 17, 115, 1998. 

Dufton P.W., Thermoplastic Elastomers, Rapra Industry Analysis Report, 2001. 

Glass transition temperature (Tg), measured by means of dynamic mechanical analysis (DMA) of E-plastomers has been measured in binary blends of iPP and E-plastomer. These studies indicate some depression in the Tg in the binary, but incompatible, blends compared to the Tg of the corresponding neat E-plastomer. This is attributed to thermally induced internal stress resulting from differential volume contraction of the two phases during cooling from the melt. The temperature dependence of the specific volume of the blend components was determined by PVT measurement of temperatures between 30°C and 270°C and extrapolated to the elastomer Tg at —50°C. 

Aaron, B.B. and Gosline, J.M., Elastin as a random-network elastomer A mechanical and optical analysis of single elastin fibers. Biopolymers, 20, 1247-1260, 1980. 

It is of interest to examine the development of the analytical toolbox for rubber deformulation over the last two decades and the role of emerging technologies (Table 2.9). Bayer technology (1981) for the qualitative and quantitative analysis of rubbers and elastomers consisted of a multitechnique approach comprising extraction (Soxhlet, DIN 53 553), wet chemistry (colour reactions, photometry), electrochemistry (polarography, conductometry), various forms of chromatography (PC, GC, off-line PyGC, TLC), spectroscopy (UV, IR, off-line PylR), and microscopy (OM, SEM, TEM, fluorescence) [10]. Reported applications concerned the identification of plasticisers, fatty acids, stabilisers, antioxidants, vulcanisation accelerators, free/total/bound sulfur, minerals and CB. Monsanto (1983) used direct-probe MS for in situ quantitative analysis of additives and rubber and made use of 31P NMR [69]. 

Lussier [71] has given an overview of Uniroyal Chemical s approach to the analysis of compounded elastomers (Scheme 2.2). Uncured compounds are first extracted with ethanol to remove oils for subsequent analysis, whereas cured compounds are best extracted with ETA (ethanol/toluene azeotrope). Uncured compounds are then dissolved in a low-boiling solvent (chloroform, toluene), and filler and CB are removed by filtration. When the compound is cured, extended treatment in o-dichlorobenzene (ODCB) (b.p. 180 °C) will usually suffice to dissolve enough polymer to allow its separation from filler and CB via hot filtration. Polymer identification was based on IR spectroscopy (key role), CB analysis followed ASTM D 297, filler analysis (after direct ashing at 550-600 °C in air) by means of IR, AAS and XRD. Antioxidant analysis proceeded by IR examination of the nonpolymer ethanol or ETA organic extracts. For unknown AO systems (preparative) TLC was used with IR, NMR or MS identification. Alternatively GC-MS was applied directly to the preparative TLC eluent. 

Deformulation of vulcanised rubbers and rubber compounds at Dunlop (1988) is given in Scheme 2.3. Schnecko and Angerer [72] have reviewed the effectiveness of NMR, MS, TG and DSC for the analysis of rubber and rubber compounds containing curing agents, fillers, accelerators and other additives. PyGC has been widely used for the analysis of elastomers, e.g. in the determination of the vulcanisation mode (peroxide or sulfur) of natural rubbers. 

Scheme 2.2 Uniroyal Chemical s analysis of compounded elastomers. After Lussier [71]. Reprinted with permission from Proceedings of the 122nd Meeting of the ACS Rubber Division, Paper No. 27. Copyright (1983), Rubber Division, American Chemical Society, Inc.

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